1. Field of the Invention
The present invention relates in general to a control mechanism of an automotive transmission, and more particularly to a shift control mechanism of a manual transmission which is particularly adaptable for use in a front-wheel-drive automotive vehicle having a transversely mounted engine.
2. Description of the Prior Art
In the transmission of the type mentioned above, the shift control mechanism is so arranged that the control rod actuated by the manual shift lever in the vehicle cabin extends perpendicular to the axis of the fork shaft on and along which shift forks slide axially. Thus, a so-called direction changing device is arranged between the control rod and the shift forks, which functions to convert the axial movement of the control rod to a sliding movement of selected one of the shift forks along the axis of the fork shaft. One of the direction changing devices is disclosed in Japanese laid-open Utility Model Application No. 48-19691, which comprises a plurality of L-shaped pivotting levers which are pivotally mounted on a common pivotting pin secured to the housing of the transmission, one end of each pivotting lever being pivotally jointed with an extension of the corresponding shift fork and the other end of each pivotting lever being selectively engageable with a head member secured to the control rod, so that upon a selecting operation of the control rod achieved by rotation thereof about its axis, the head member is brought into engagement with the other end of one of the pivotting levers, and upon a shifting operation of the rod achieved by the axial movement thereof after the selecting operation, the selected pivotting lever is rotated about the common pivotting pin in a given direction to move the corresponding shift fork along the fork shaft thereby to establish a certain gear ratio.
In usual direction changing devices including one shown by the above-mentioned Application, however, the pivotal connection or articulated connection between each pivotting lever and the extension of the corresponding shift fork has caused a considerable abrasion at the surface of the shift fork extension to which the pivotting lever is slidably and pivotally engaged. In fact, hitherto, the shift forks and thus the extensions are constructed of a light metal such as aluminum for the purpose of improving movability of them, while, the pivotting levers are constructed of a rigid strong metal, such as steel, for bearing the operation load applied thereto. In order to solve such abrasion problems, several measures have been proposed, one being to line the contacting surfaces of the shift fork extensions with a high wear resistant material, and another being to fix wear resistant pieces to the contacting surfaces to the extensions tightly, for example, by means of a dovetail joint method. However, these conventional measures fail to show practically satisified results because of their costly production method or poor productivity.